Beer Color is Not as Clear as it Seems

I recently attended a weeknight beer event being run by a friend of mine who works for Fat Head’s Brewery, one of Ohio’s best brewers of intense hoppy ales, nuanced traditional German styles, and everything in between.

The night was sultry and the air was close, and it had been raining intermittently out of a low, gray sky for most of the afternoon. Consequently, my friend Richard (“Head Hop Wanderer” at Fat Head's) was plying patrons with two of his lighter brands: Bumbleberry, a honey blueberry ale available year-round but most beloved in the heat of summer, and Sunshine Daydream, a fantastic session IPA named, like many Fat Head’s beers, as an homage to the Grateful Dead.

Richard was sampling customers, working the room, talking beers and distributing samples as a beer rep is wont to do. He very graciously offered to buy me a beer; I ordered a Sunshine Daydream, and the bartender set my 20oz glass down right next to the bulbous, fishbowl-like pitcher from which Richard had been pouring samples of the same beer.

And a thought immediately struck me: beer color is strange.

Miles LiebtagThat's the same beer, in different containers.

Of all the different ways we’ve collectively agreed to quantify beer attributes, color is the most deceptively simple, I think. After all, it’s the only attribute that relies on a single sense (that is, sight – all other qualitative attributes are experienced through some combination of smell, taste, and physical sensation), and it’s the one that in theory should be the easiest to agree on. Although there’s some amount of Philosophy 101 at play in pondering whether your brown is the same as my brown, within a fairly narrow field we’ll almost certainly both agree on what brown is, even if we may differ substantially on whether a given beer smells more like pomegranate or lychee.

And we can break colors down to numbers in a way that we might struggle to do with tastes and textures. While you might describe a beer as being “chestnut with garnet highlights,” you can also assign it a numerical color value (SRM or Standard Reference Method), but both mean, basically, brown, or maybe reddish-brown.

Assigning flavor and aroma descriptors like “passionfruit” or “bread crust” to a beer is a way to try and express verbally (and thereby enable shared knowledge about) a sensory experience that really isn’t easily quantifiable – we can probably both agree pretty easily on a common “brown,” but agreeing that a certain flavor note is “bread crust” as it presents in a colloidal solution of 6% ethanol by volume in association with dozens of different esters, phenols, alcohols and acids is a fair bit less straightforward.

Beer color, despite the easy number, isn’t straightforward either. Although you can crack any beer book and find style descriptions that contain quantitative data on beer color – usually expressed in SRM, or Standard Reference Method, about which more presently – that number and the color scale that goes along with it does relatively little to explain why a tall glass and a fat pitcher of the same beer should look so radically different. So what gives?

Mike Duesenberg / Good Beer HuntingSRM values with color examples.

The color of beer is a reflection (or perhaps refraction) of the color of the malt used to make that beer. Part of beer recipe formulation is considering what color one wants the ultimate, fermented beer to be: a tawny porter, a deep orange IPA, an inky black stout, etc. Color is, for better or worse, one of the principal ways that we identify style; while the past decade or so of craft brewing has seen brewers using color to experiment with and defy our expectations (in the case of the “blonde stout” or “Cascadian dark ale,” whose star has so precipitously fallen), color still communicates a lot to the drinker about how a given beer is “supposed” to taste.

And so when a brewer plans a recipe to arrive at a certain color, she is using an abstract quantifiable to determine what the color of the beer will be given the malt she is using – usually the Standard Reference Method of calculating beer color, also known as SRM. All malt, whether purchased by a homebrewer or large commercial brewery, should come with a spec sheet that lists its SRM, and “the SRM value of the malt is roughly equal to the wort color achieved when 1 lb of malt is mashed in 1 gallon of water” (Mallet 17). So if one were to make a simple tea of some crushed barley malt with those proportions, the color of the resultant liquid should closely match that of the malt’s SRM value as indicated on the SRM color chart.

Still with me? Think of SRM as color “points” – the higher the number, the darker the color of the malt and by extension, the beer. The scale begins at 2-3 SRM (“pale straw”) and tops out at 40 SRM (“black”). Brewers make an educated guess at beer color by making calculations based on the SRM scores of all the malts they use in a given recipe, at given amounts.

Beer color profoundly influences our perceptions, not just of style, but of flavor.”

This is because lots of other factors also influence perceived beer color, such as the concentration of proteins and polyphenols, the pH of the solution, and brewhouse procedures. Long boil times and decoction mashes (wherein a portion of the mash is removed and boiled to deepen and concentrate malt flavor) can also darken beer beyond its malts’ calculated SRM potential – if you’ve ever made a caramel from white sugar on the stovetop, you get a sense of how heat and time can effect a color change. Beyond the brewhouse, age can also darken a beer, especially lighter-colored ones, as oxidation takes its toll.

SRM is a measure of color density, determined by the amount of light at a given wavelength that is absorbed by a liquid sample at a specific volume. The perceived color of the Fat Head’s Sunshine Daydream in the picture above is vastly different from pitcher to glass – more of the light is absorbed by the higher density of particulates suspended in the liquid in the fat, squat pitcher than the tall, skinny glass, so the former has a “pale amber” color (say, SRM ~9), while the latter appears “pale gold” (perhaps SRM ~4).

A lab-tested sample would of course reveal that they are of course both the same color, and the color in the glass is almost certainly closer to the SRM originally calculated by the brewery in recipe formulation.

As with so much else in beer (and life), color can be as simple or as complex as you’d like to make it. While I can just barely grasp the basics of the science behind beer color, I know very well that it profoundly influences our perceptions, not just of style, but of flavor.

The next time you’re at a bottle share (or just drinkin’ on the porch), try a little experiment: blind taste a beer in an opaque container. Think through what you’re tasting: malty? Hoppy? Heavy? Light? Strong? Sessionable? Now, take an educated guess at the color. Did your impressions match your supposition?